Thrush retired at the end of last season, but the former All Blacks lock was sent an SOS by new Force coach Simon Cron after losing Wallabies star Izack Rodda (foot fracture) and Ryan McCauley (shoulder).
The Rebels were on track for victory after opening up a 24-10 lead late in the first half of Saturday night's match.
But the introduction of Thrush early in the second half marked the start of the Force's comeback.
The Force hit the lead in the 64th minute following tries to Tom Horton and Hamish Stewart, only for Rebels star Reece Hodge to level the scores three minutes later with a 52-metre penalty.
But Thrush was having none of it.
With blood streaming out of his nose from an earlier incident, the 37-year-old sucked in deep breaths and barged over the line in the 72nd minute to score what ended up being the match-winning try.
"A couple of weeks ago we lost one of our locks to a shoulder injury, and I just gave him a wee tap on his shoulder and said, 'start training'," Force coach Simon Cron said of Thrush.
"I've been watering his plant ever since - just building him up, telling him he's big, he's strong, he's fast. He showed all of that tonight.
"He's a guy that if you're running out of the trenches, you want him behind you. He was a man mountain today when he came on."
The Rebels missed a whopping 35 tackles to the Force's 13.
"Good first half, disappointing second half," Rebels coach Kevin Foote said.
"We didn't play the territory game, our discipline let us down, and they slipped too many tackles. They got momentum off that and capitalised."
The Force lost Wallabies hooker Folau Fainga'a and star winger Manasa Mataele with achilles problems before the match.
Hooker Feleti Kaitu'u went off injured late in the first half in another blow for the Force.
Rebels flyhalf Carter Gordon scored the first try in the 16th minute when he intercepted a loose pass from Ian Prior and ran 50 metres untouched to the line.
Former Force scrumhalf Ryan Louwrens made it 15-3 when he dived over the line after the ball had bobbled out of a collapsed rolling maul.
The Force hit back through a try from Tom Robertson in the 33rd minute courtesy of a nice break from Toni Pulu.
But a try to stand-in Rebels captain Brad Wilkin gave the visitors a 24-13 lead at half-time.
The complexion of the game changed in the 50th minute when Rebels winger Lachlan Anderson was yellow carded for an obvious foul as the Force were close to scoring a try.
Thrush hit the next ruck hard, and Horton barged over for a try that reduced the margin to just four points.
The Force hit the lead in the 64th minute when Stewart touched down after a successful rolling maul.
Hodge's penalty momentarily halted the Force's momentum, before Thrush stepped up to the plate to score the winner.
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